Mandrel for driving pile shells



C. B. HOPPE MANDREL FOR DRIVING PILE SHELLS April 4, 1961 2 Sheets-Sheet1 Filed Feb. 26, 1957 INVENTOR Clemens B. Hoppe BY W RNEYS C. B. HOPPEMANDREL FOR DRIVING PILE SHELLS April 4, 1961 2 Sheets-Sheet 2 FiledFeb. 26, 1957 FIG.5.

37 -IIIIIIII INVENTOR.

B. Hoppe Clemens M 5% Y01Z M f7 fv A TTORNE YS United States MANDREL FORDRIVING PILE SHELLS Clemens B. Hoppe, Ridgefield, NJ, Hercules Con-'crete Pile 'C0.,Piers 1 and 2, West New'York, NJ.)

Filed Feb. 26, 1957, Ser. No. 642,418

6 Claims. (Cl. 6153.72)

This invention relates to apparatus for. driving metal casings, usuallycalled shells, into the earth for forming concrete piles, and has foritsv object the provision of an. improved expansible'and collapsiblemandrel for driving.

corrugated shells. My invention is, concerned with mandrels of the typehaving an outer mandrel partcomprising a plurality of longitudinallysegmented exterior mem-' bers (usually called leaves) which can beexpanded and contracted by an innermandrel member. My invention providesa plurality of rod segments secured to the outsides of the leaves anddisposed in spaced-apart relation with respect to the longitudinal axis.of the mandrel. These rod segments have utility when used in drivingshells having corrugations, the rods being arranged to, span thecorrugations at small acute angles, whereby the rodsjbecome embeddedinto the corrugations of the shell when the leaves are expanded in thedriving of the shell.

The improved mandrel of my invention may be advantageously used indriving shells having helical corrugations in which-case the rods areattached 'to. the leaves: at.

atent O 2 which receives the driving blows of the hammer. The tubularmember 1 has upper and lower bosses 10 and 11 which have downwardly andinwardly sloping wedge surfaces 12 and 13 respectively. Any suitable.number of such bosses may be provided at spaced intervals. The tubularmember 1 has a plurality of elongated slots 14 spaced apartcircumferentially and in the longitudinal direction of the member.Beneath each slot the tube is enlarged and provided with an upwardlyand-outwardly projectingwedge surface 15. While only one of such slotsand "surfaces are shown in Fig. 1 it is to be understood that anysuitable number of these may be provided one of the leaves as shown inFigs. 2 and 3.

The outer mandrel member 2 comprises three leaves 20, 21 and 22 whichare each segments of about 120 of arc and, when in their contractedposition as shown in Figs. 1 and 2, the assembly is circular incross-section. The assembled and contracted leaves form a continuoustube that fits inside the pile shell or casing S. When the leaves arecollapsed as shown in Figs. 1 and 2, the exteriors of the bosses 10 and11' make close contact with the inner face of the leaves. Theupperportion 3 has three longitudinally staggered openings 24 '(one oppositeeach leaf) in each of which a floating cam lever 25 is inserted. Onepart of each lever projects into an elonat longitudinally spacedintervals, each being opposite gated slot 27. in its oppo-site leaf andthe other part projects into an opening 28 in thestem 5. The levers andtheir respective slots in the leaves and openings in the stem are spacedapart or staggered in the longitudinal direction of the mandrel. The camlevers are referred tolas being floating since they are not mounted'onpintles and are free to move, to a limited extent, relative to the stem5, the inner mandrel, and the segment leaves.

The upper portion of the mandrel is provided with a loose. fittingcollar C which is suspended from the hammercrane by a cable C. Thiscollar is the means by which the mandrel is pulled out of the shell, andsince it hangs loose during driving, the mandrel is free to rotate withthe shell which has the effect of being threaded into the earth due tothe helical corrugations. Another very important function of the loosecollar is in its securing facilitates driving shells in severe andabnormal condi- V tions. The-improved mandrel compensates for.variations in the shelland mandrel.

The inventionis applicable generally to. mandrels 'ha'vr ing expansibleand collapsibleisegment's. or'leaves,andf for the purpose ofillustration. will. be described :in' connection with ajmandrel;embodyingyfeatnres of the. mau drelgof myco-pending patent applicationSerial-Nd. 550, 528, filed December 2, 1955, and now abandoned, 'of?which this application isa continuation-impart.

In the accompanying. drawings:

Hg. 1 is a vertical, fragmentary view, partly in section, ofta mandrelembodying the invention shown in its fullycontracted or collapsedposition;

Fig. 2risanenlargqdsectional view at .-2'2of Fig. 1; i Fig. 3 is a view,similartoFig- 2 showing the mandrel in its er ande resit m V V a Fig. 4is anenlargedifragmentary view of a part-of Fig.

1 4$ t hepQSition. of the rods and corrugations igs- 5 and; 3 iewssimilartoFig. llrbut showing.

era i dilf ren irel t v positions i The, improvedmand-rel-of theinvention illustrated in having upwardly and downwardly slopingsurfaces. 32" l thedrawings comprises an-inner mandrel member 1 and:

ma ter mandrehmember The inner mandrel membei isintlie' formof acontinuous tube, the upper portion a 3 of whjich hasya' cylindricalopening .4 in which the stem 5 it rate;- l ha aa .aaar eaa;engages;

of the cam levers in their slots, thuseliminating attach ing pins. 7 I

i The leaves of the outer mandrel member are each provided with upperand lower wedge segments 30 and'31 and 33 respectively which operativelyengage the wedge surfaces 12 and 13 of the inner mandrel member in e x-,

panding the leaves. Each leaf has one or more cam brackets '34attached'thereto and located in staggered rela tion in the longitudinaldirection of the mandrel which are arranged to project through the slots14 in the inner mandrel member. Each cam bracket hasa'downwardlyandinwardly sloping surface 36 which makes bearing contact with one ofthe sloping surfaces 15 to draw the leaves inwardly to their collapsedposition when the inner mandrel is pulled upwardly.

The cam brackets extend downwardly inside the hol;v low mandrel adistance such that when the mandrel is, removed from the pile shell andthe inner mandrel and the segmental leaves are moved relatively tothemaxi; mum distance in a direction to extend the leaves, the free I ordistal ends of, the cam levers still lie below the lower ends of theslots and-opposite a portion of the wall of thev inner mandrel, so thatthe leaves are held to the inner mandrel and cannotfall away.

It is to be understood that the mandrel can be}ofany.- suitable lengthandmay have alower foot portionof: y. issiraqfiaa twa qnl a xampl as ownt! Patented Apr. 4, 1951 said patent application, for engaging the lowerclosed portion 37 of the casing.

At intervals spaced in the longitudinal direction of the mandrelaxis aplurality of small rods R are attached as by welding to the exteriorsurfaces of the leaves 20, 21 and 22. These rods may be of any suitablecross-sectional shape, such as round or half-round, and areadvantageously spaced apart a distance corresponding to the distancebetween adjacent corrugations of the shell. When shells having helicalcorrugations are to be driven, such as illustrated in the drawings, therods R are arranged to embrace planes at right angles to thelongitudinal axis of the mandrel. As thus arranged the rods are disposedat small acute angles with respect to the corrugations, and when therods are in engagement with the corrugations they are in at leastpartial spanning position. It is to be understood, of course, that whenthe corrugations of the shell are not helical, being in planes at rightangles to the longitudinal axis, the rods are so angularly attached tothe leaves that they form small acute angles with respect to thecorrugations.

Fig. 1 shows the improved mandrel of the invention inserted inside acylindrical corrugated metal shell S of a. type widely used for drivinginto the earth to form concrete piles. The head 9 is shown in itselevated position prior to driving the mandrel. In this position one endof each of the cam levers 25 is in the upper part of its slot 27 and theother end is in bearing contact with the stem where it enters the slot28. The surfaces 12 and 13 are above and out of contact with thesurfaces 32 and 33. However, the surfaces 36 of the cam brackets 34 arein bearing contact with the surfaces 15 and the leaves are accordinglyheld in their inner collapsed positions.

In driving the shell S into the earth from the position shown in Fig. 1,an initial gentle pushing on the head 9 is sufficient to force theentire inner mandrel member 1 and the leaves 20, 21 and 22 downwarduntil the leaves engage a foot (not shown) at the lower end of themandrel which in turn engages the end 37 of the casing. The respectiveparts then are in the position shown in Fig. 5. This downward movementof the inner mandrel member removes the cam brackets 34 from engagementwith the surfaces 15 permitting the leaves to move downwardly and as theinner member continues to move downwardly the surfaces 12 and 13 engagethe surfaces 32 and 33 respectively and force the leaves to the fullyexpanded positions shown in Figs. 3, 4 and 5 and into close contact withthe shell S. In this position the driving head 9 bears on both theleaves and the inner mandrel member and the rod segments R engage thecorrugations of the shell as shown in Figs. 3 and 4. The rods spanportions of the corrugations by reason of their angular relation andbite into or become partially embedded in those portions of thecorrugations with which they make direct contact.

When the shell has been completely driven the mandrel is removed asfollows: An upward pull is applied by the driving machine to the cablesC on the collar C and in the initial upward movement of the head, shownin Fig. 6, the cam levers 25 come into action in collapsing the outermandrel member. In this initial action the cam levers perform threeimportant functions, namely, their outer ends hold the leaves down, theybreak the contact of the leaves with the inner mandrel member which arebound by the force of the pile hammer, and they lock the stem 5 of thehead to the upper portion 3 of the inner mandrel member. As the innermandrel member is pulled upwardly, one end of each cam lever engages thebottom of slot 28 while the upper mid-point 25' of the lever contactsthe upper portion of the slot 24 in upper portion 3 of the innermandrel. As the stem 5 isfurther withdrawn the opposite end of the leverbears down on the leaf slot 27, the mid-point bearing on the upperportion of the slot 24 lifts the inner mandrel memher sufficiently tobreak the contact between the inclined surfaces of the leaves and theinner mandrel member. As a result, the first two functions of the camlevers are performed. As stem 5 is further withdrawn the cam levers lockagainst the inner member 1 and stop the sliding action of the stemtherein. As the inner mandrel continues to move upward the surfaces 12and 13 move out of contact with the surfaces 32 and 33, as shown inprising a plurality of leaves, wedge means on the inner mandrel memberfor expanding and collapsing the leaves, a drivinghead having a stemslidably mounted in the inner mandrel member, the leaves, the innermandrel member and the stem having circumferentially-spaced aligned,longitudinally-extending slots, a cam lever floatingly mounted in eachof the aligned slots, the shape of each cam lever and its size relativeto the size of the aligned slots in which it is mounted being such thatwhen the head and stem each initially are lifted in collapsing theleaves, the outer end portion of each cam lever bears on its associatedleaf at the lower end of the slot therein, holding it down, anintermediate upper surface portion bears on the inner mandrel member atthe upper end of theassociated slot therein and the inner end portion isengaged by the portion of the stem at the lower end of its associatedslot and a force is exerted by the stem on the cam lever in a directionto lift the inner mandrel member relative to the leaves to break thecontact between the wedge means on the inner mandrel member and theleaves, and on continued upward movement of the head and stem, the camlevers lock the stem and inner mandrel member together for upwardmovement.

2. The improved mandrel set forth in claim 1 in which a collar surroundsthe outer mandrel member subjacent the driving head and is rotatablerelative thereto, the collar has a skirt portion extending downwardly toa position at least opposite the cam levers when the collar is raised,the inside diameter of the collar is larger than the outside diameter ofthe leaves when the leaves are expanded in the casing so that the leavesdo not bind on the collar and prevent relative movement between thecollar and the leaves, but is sufficiently small to hold the cam leversin their operative positions in the slots.

3. The improved mandrel as set forth in claim 1 in 'which the alignedslots in the leaves, the inner mandrel member and the stem are locatedat different vertical levels.

4. The improved mandrel as set forth in claim 1 in which each of saidleaves has cam brackets extending 'inwardly. therefrom, said cambrackets each have a portion extending through a slot in the innermandrel member and which includes cooperating vertically inclinedsurfaces carried, respectively, by the portions of the cam bracketswhich extend through said slots and the inner mandrel member, whichcooperating inclined surfaces are operative upon upward movement of theinner mandrel member relative to said leaves to collapse said leaves.

5. The improved mandrel of claim 4 in which a collar surrounds the outermandrel member subjacent the driving head and is rotatable relativethereto, the collar has a skirtportion extending downwardly to aposition at least opposite the cam levers, the inside diameter of thecollar is larger than the outside diameter of the leaves when the leavesare expanded in the casing so that the leaves donot bind on the collarand prevent relative movement between the collar and the leaves, but issufficiently small to hold the cam levers in their operative positionsin the slots.

6. The improved mandrel for driving metal shells which comprises amandrel including an inner mandrel member, an outer mandrel membercomprising a plurality of leaves, means on the inner mandrel member forexpanding and collapsing the leaves, a driving head non-rotatablyconnected to the inner mandrel member, a separate collar surrounding theouter mandrel member and directly under the driving head and rotatablerelative thereto, the inside diameter of the collar being larger thanthe outside diameter of the leaves when the leaves are expanded in thecasing so that the leaves do not bind on the collar and prevent relativemovement between the collar and the References Cited in the file of thispatent ing means.

UNITED STATES PATENTS Upson et al Sept. 26, Johnson Nov. 28, Cobi Jan.13, Smith July 27, Riker Apr. 10, Burrel Apr. 15, Iourdain Jan. 20, CobiApr. 14,

FOREIGN PATENTS France Feb. 3,

